HAL Portal UBS (Université Bretagne Sud)
Not a member yet
14201 research outputs found
Sort by
Bridging the Gap Between Bioarchaeology and Cultural Studies in Understanding Transitions in the Past
No full textInternational audienceTransitions during prehistoric and historical periods cannot be fully understood as mere adaptations to new economic, subsistence, or production systems. Instead, these shifts are intricately embedded within complex social contexts, involving cross-community relationships, migrations, and the transmission of knowledge, ideas, and technologies. These processes vary significantly across different geographical and chronological settings, shaped by the diverse modes of interaction between distinct population groups. While bioarchaeological research provides valuable insights into these transitions—often highlighting large-scale patterns of human migration, genetic intermixing, and broad demographic shifts, especially in the case of ancient DNA studies—these perspectives do not always align with the detailed, context-specific findings offered by cultural studies. Cultural studies, with their focus on material culture, social identities, and the nuanced transmission of knowledge and technologies, often reveal more localized and intricate patterns of change. The challenge lies in reconciling these two approaches, as they often operate on differing temporal and spatial scales. This session aims to foster a critical dialogue between bioarchaeological and cultural perspectives, with the goal to: (i) refine and question the temporal frameworks of these processes; (ii) identify patterns of interaction that may either converge or diverge across disciplines; and (iii) explore the rhythms of contact and exchange, and their effects on human behaviour, social organization, and technological evolution. Through cross-disciplinary discussions, we seek to bridge the gap between bioarchaeological narratives and cultural studies.We invite contributions from around the world that explore mobility, migration, and interactions among societies undergoing these transitions. Researchers from bioarchaeology, material culture studies, residue analysis, ancient DNA research, and related fields are encouraged to participate. By bringing together diverse perspectives, we hope to deepen our understanding of these transitions and integrate both large-scale and fine-grained views into the broader historical narrative
Sallés Vilaseca, Núria, La política internacional de Giulio Alberoni: el desafío al orden europeo en el reinado de Felipe V, Valencia, Albatros Ediciones, 2024, 222 págs. ISBN: 9788472744103
No full textInternational audienc
Numerical analysis of the large deviation regime of a kinetic equation with a nonlocal Hamilton-Jacobi limit
No full textWe develop and study an asymptotic-preserving (AP) numerical scheme for a linear kinetic equation in a large deviation regime. After applying a Hopf-Cole transform to the distribution function, the system exhibits the behavior of rare events, which in the limit is governed by a non-standard, nonlocal Hamilton-Jacobi equation, as identified in [E. Bouin et al., J. Lond. Math. Soc., II. Ser., 2023].The proposed scheme efficiently handles the stiffness introduced by scaling, with a computational cost that remains uniform with respect to the small parameter. It takes advantage of the conservation properties of the original kinetic model to overcome the numerical challenges posed by stiffness. The scheme satisfies a discrete maximum principle, preserves equilibrium states, and correctly captures the asymptotic limit, recovering the viscosity solution of the limit nonlocal Hamilton-Jacobi equation.As the limit problem is non-standard, convergence results from the literature are not directly applicable. We introduce new analytical tools based on a discrete representation formula that links the numerical scheme with the continuous setting. This allows us to prove the convergence and establish key structural properties of the method. Numerical tests support the analysis and illustrate the robustness of the scheme and the original behavior of the limit system
Contribution à l’étude de la réponse de matériaux hétérogènes soumis à des sollicitations environnementales et mécaniques
No full textThis document presents a summary of approximately fifteen years of applied research into the response of heterogeneous materials to environmental and mechanical loading. One area of focus within this research is the response of metallic materials to wide temperature variations, an oxidizing environment, and mechanical loading. Materials under investigation include zirconium alloys, chromium-coated zirconium alloys, and a martensitic steel. The following issues are addressed: high temperature corrosion, mechanical behavior, failure, and the influence of microstructural changes, and heterogeneities induced by temperature variations and corrosion (phase changes and oxygen and hydrogen absorption, for example). Another area of focus in the research is the response of heterogeneous polymer-based materials to cyclic mechanical loading in environments (temperature and humidity in particular) that may vary in certain cases. The work presented examines the thermomechanical behavior and fatigue life of a range of materials, including short fiber-reinforced thermoplastic matrix composites, long fiber-reinforced thermoset matrix composites, and elastomer foams. The methodology employed integrates multiscale experimental characterization, modeling, and numerical simulation.Ce document fait la synthèse d’une quinzaine d’années de recherche, à vocation appliquée, sur la réponse de matériaux hétérogènes soumis à des sollicitations environnementales et mécaniques. Une partie de ces activités de recherche porte sur la réponse de matériaux métalliques soumis à des variations importantes de température, à un environnement oxydant et à des sollicitations mécaniques. Les matériaux étudiés comprennent des alliages de zirconium, des alliages de zirconium revêtus de chrome et un acier martensitique. Les problématiques abordées incluent la corrosion à haute température, le comportement mécanique, la rupture, et l’influence des évolutions microstructurales et des hétérogénéités induites par les variations de température et la corrosion (changements de phases et absorption d’oxygène et d’hydrogène par exemple). Une autre partie des activités de recherche présentées porte sur la réponse de matériaux hétérogènes à base de polymères soumis à des chargements mécaniques cycliques, dans des environnements (température et humidité notamment) susceptibles de varier dans certains cas. Les travaux exposés portent sur le comportement thermomécanique et la tenue en fatigue de différents matériaux incluant des composites à matrice thermoplastique renforcée de fibres courtes, des composites à matrice thermodurcissable renforcée de fibres longues et des mousses élastomères. La démarche mise en œuvre associe caractérisation expérimentale, modélisation et simulationnumérique
A Coupled Criterion-based approach to develop an adherence test for adhesively bonded joints
No full textInternational audienc
Evolution of the palynomoprh communities of a highly anthropised system : The Rance estuary seen through dinocysts, algae and Ciliates over the last century
No full textInternational audienc
Dynamic Incentive Design for Green Bonds: Signaling, Reputation, and Optimal Subsidies.: A Stackelberg Model under Asymmetric Information
No full textThis paper develops a dynamic Stackelberg model to analyze how a regulator should design incentives in green bond markets when information is asymmetric, firms face heterogeneous costs, and reputational payoffs evolve over time. Firms differ in their environmental type and choose to issue green bonds if their private cost falls below an endogenous threshold shaped by economic returns, policy incentives, and public beliefs about their quality. These beliefs are updated through Bayesian inference from observed issuance behavior, creating a link between current actions and future reputational rewards. The regulator seeks to maximize dynamic social welfare by trading off the immediate benefits of greater issuance against the fiscal cost of subsidies and the longer-term compliance gains generated by reputation. Under tractable functional assumptions, we derive closed-form expressions for the optimal subsidy and compare static (myopic) and dynamic policy rules. The analysis shows that when reputational spillovers are strong, dynamic optimization leads to lower subsidies because belief updating amplifies future participation. Conversely, when beliefs adjust slowly or firm types are poorly distinguishable, higher subsidies are needed to sustain credible signaling.The results highlight the importance of reputation as a cost-effective complement to direct subsidies and offer guidance for scaling green finance while containing public expenditure.</div
Un passé dépassé ? Les mémoires protestantes des guerres de Religion (vers 1685-2022) [position de thèse]: Thèse d’histoire moderne et contemporaine, Le Mans Université, 2024, 639 p.
No full textAlors que les protestants français cultivent le souvenir de la Saint-Barthélemy depuis le XVIe siècle, le contexte des guerres de Religion (1562-1598), dans lequel s’inscrivent les célèbres massacres, semble beaucoup moins retenir leur attention. Or ces troubles civils et religieux représentent une crise majeure de l’histoire nationale et voient, pour la première fois, les protestants français prendre les armes en grand nombre. C’est tout l’objet de la thèse de Laurent Ropp, soutenue le 22 novembre 2024 à Le Mans Université, que de saisir, dans la longue durée, les mémoires de ces conflits dans les communautés issues de la Réforme. Des années 1680, marquées par une controverse interconfessionnelle sur les guerres de Religion, au 450e anniversaire de la Saint-Barthélemy (2022), cette recherche éclaire la manière dont le présent influence le souvenir des luttes du second XVIe siècle et examine dans quelle mesure ces conflits du passé restent d’actualité dans les siècles qui les ont suivis. Un vaste corpus imprimé, auquel s’ajoutent des sources plus originales, comme 526 réponses à un questionnaire en ligne, est mobilisé afin de rendre compte des réactivations mémorielles et de mettre au jour les continuités et les transformations des représentations et des usages des troubles. Centrée sur les réformés français tout en intégrant les luthériens et les évangéliques de l’Hexagone ainsi que les communautés protestantes de trois pays d’accueil de la diaspora huguenote, cette investigation offre également une réflexion sur l’unité et la pluralité des mémoires huguenotes
Influences of land use and depth profile on the characteristics of microplastics in agricultural soils
No full textInternational audienceTerrestrial soils are an environmental compartment in which microplastics are known to accumulate. Compared to the surface water of global oceans, soils contain more microplastics, however they are less well studied to date. In particular, the applications of wastewater and corresponding sludge as fertilizers are a major source of microplastics to agricultural soil, as they include washing machine effluent which is often concentrated in polyester fibres. Other relevant microplastic sources include plastic mulching, netting, greenhouses, plastic drainage pipes, and atmospheric deposition. The characteristics and transfer dynamics of microplastics between different environmental compartments including soil in the same agricultural watershed are not well understood. Additionally, very limited information is known on the stock of microplastics in soils. In this work, a long-term French research site, the Orgeval watershed (104 km2), was sampled for soil. This watershed, located slightly beyond the extremities of the Eastern Parisian suburbs, is composed largely of intensive cereal crops and minimal urban zones. Nine locations within the watershed were composite sampled at the soil surface including locations both upstream and at the watershed outlet. These soil samples were derived from various land use areas including agricultural zones such as tilled or undisturbed agricultural fields, greenhouses, and drainage canal riverbanks, plus soil in forested areas and an urban green space. Of these land use types, greenhouse soils demonstrated the highest concentrations of microplastics in surface soils up to 11,200 MPs/kg, where polyethylene and polypropylene made up the majority of the polymers identified. In comparison, forest soils contained far fewer microplastics up to a concentration of 880 MPs/kg. Soil cores were also collected from two of these sites down to a depth of 60 cm, the typical maximum tilling depth used in this watershed. The most noticeable concentration decrease was observed between soil samples collected at the soil surface versus a further 20 cm below it. This study helps better understand the sources of microplastics as well as their fate in agricultural soils